Pseudo push determination method in touch sensor without force sensor

ABSTRACT

A push determination determines whether an indicator has pushed or touched a local region of an interface in a touch sensor used with a display panel that displays a graphical user interface. A method according to the present disclosure includes: outputting area data corresponding to a size of a tracking region and sum total data corresponding to a sum total value of level values at positions included in the tracking region; and, in a case where the sum total data indicates the sum total value is greater than a predetermined sum total value, determining an event corresponding to a push operation is to be output when the area data indicates a second area value smaller than a first area value and determining an event corresponding to a touch operation is to be output when the area data indicates the first area value.

BACKGROUND Technical Field

The present disclosure relates to a touch detection method in a touchsensor.

Background Art

A force-sensing touch sensor including a force sensor and configured todetect an operation (hereinafter, push operation) of applyingpredetermined force to an indication position is known (U.S. Pat. No.9,798,409).

In a touch sensor without a force sensor, a push determination functionfor pseudo determination of a push operation is realized. Particularly,a push determination function is realized, in which data correspondingto the push operation is output when force is locally applied, such asin a case of a strong push with a fingertip, and false detection of anoperation as the push operation is prevented when capacitance is changedin a wide range, such as when a finger is attached to the touch sensor.

BRIEF SUMMARY

A first aspect of the present disclosure provides a method performed byan integrated circuit connected to a touch panel used with a displayapparatus that displays a graphical user interface, the methodincluding: acquiring level values indicating changes in capacitance atpositions in a two-dimensional region of the touch panel; detecting atouch to the touch panel by an indicator based on a maximum value of thelevel values at the positions in the two-dimensional region; specifyinga tracking region of a position where the maximum value is output;outputting area data corresponding to a size of the tracking region andsum total data corresponding to a sum total value of the level values atthe positions included in the tracking region; and, in a case where thesum total data indicates the sum total value is greater than apredetermined sum total value, (a) determining an event corresponding toa push operation is to be output when the area data indicates a secondarea value smaller than a first area value, or (b) determining an eventcorresponding to a touch operation is to be output when the area dataindicates the first area value.

A second aspect of the present disclosure provides a method performed byan integrated circuit connected to a touch panel, the method including:acquiring level values indicating changes in capacitance at positions ina two-dimensional region of the touch panel; detecting a touch to thetouch panel by an indicator based on a maximum value of the level valuesat the positions; outputting sum total data of the level values of atracking region that is positioned around a position where the maximumvalue is output; acquiring an amount of time change of the sum totaldata; and determining whether an event corresponding to a touchoperation is to be output or an event corresponding to a push operationis to be output based on the amount of time change of the sum totaldata.

According to the first aspect of the present disclosure, the pushoperation is extracted based on the sum total data of the signal levels,and whether the value of the sum total data is in a local range or in awide range is determined based on area data S. This enables distinctionaccording to a signal level value per unit area. This can realize a pushdetermination function, in which data corresponding to the pushoperation is output when the change level of the capacitance is locallyincreased by a strong push with a fingertip, and false recognition of anoperation as the push operation is prevented when the change incapacitance is in a wide range such as when a finger is attached to thetouchpad.

According to the second aspect of the present disclosure, the positionof the tracking region R and the amount of time change dΣ of the levelvalues C of the sum total data Σ are used to determine whether theamount of time change dΣ at a predetermined position is increased. Thiscan improve the determination accuracy of the push determination fordetermining whether the push operation is performed or the touchoperation is performed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic diagram of a touch sensor that performs a methodaccording to one or more embodiments of the present disclosure;

FIG. 1B is a schematic diagram describing a push determination functionof the touch sensor;

FIG. 1C is a schematic diagram describing the push determinationfunction of the touch sensor;

FIG. 2 is an overall flowchart of a push determination method accordingto one or more embodiments of the present disclosure;

FIG. 3 is a flowchart of a touch detection at S100;

FIG. 4A depicts a state (touch operation state) in which an indicatorweakly touches a panel;

FIG. 4B depicts an example of a two-dimensional distribution of levelvalues C in a weak touch operation state;

FIG. 5 is a flowchart of touch detection involving push determinationaccording to a first embodiment of the present disclosure;

FIG. 6A depicts a state (a) of a strong push with a fingertip (pushoperation);

FIG. 6B is a two-dimensional distribution map of signal levels of thestate (a);

FIG. 7A depicts a state (b) in which capacitance changes in a widerange;

FIG. 7B is a two-dimensional distribution map of the signal levels ofthe state (b); and

FIG. 8 is a flowchart of touch detection involving push determinationaccording to a second embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present disclosure will now be described indetail with reference to the attached drawings.

First Embodiment

FIG. 1A is a schematic diagram of a touch sensor 1 common to theembodiments of the present disclosure.

The touch sensor 1 is a touch sensor without a pressure sensor, and morepreferably, the touch sensor 1 is a capacitive touch sensor.Specifically, the touch sensor 1 includes M row electrodes Y0 to YM-1(hereinafter, referred to as row electrode group Y), N column electrodesX0 to XN-1 (hereinafter, referred to as column electrode group X), andan integrated circuit 10 connected to the row electrode group Y and thecolumn electrode group X. For example, the integrated circuit 10includes a processor and a memory storing instructions that, whenexecuted by the processor, cause the touch sensor 1 to perform parts ofthe processes described herein.

The integrated circuit 10 performs mutual-capacitance touch detection bysupplying signals to the row electrodes Y and detecting the signalsthrough the column electrodes X to detect an amount of change incapacitance (hereinafter, level value C) at each of M×N intersectionpoints formed by the row electrodes Y and the column electrodes X.

The touch sensor 1 is used as an input interface of an electronic devicenot illustrated. The row electrodes Y and the column electrodes X of thetouch sensor 1 are provided to overlap with a display panel 2(hereinafter, panel 2) of the electronic device. The integrated circuit10 detects an approach of an indicator 3 to the panel 2 to detect achange in the level value C. The integrated circuit 10 performs touchdetection involving push determination described later and outputs anevent Σ (none N, touch event Etd, or push event Epd) according to adetermination result of the push determination to a host controller 20of the electronic device.

FIG. 1B is a schematic diagram describing a first state determined inthe push determination of the touch sensor 1. The host controller 20 ofthe electronic device displays various graphical user interfaces on thepanel 2. In the example of FIG. 1B, the host controller 20 displays arectangular region 4 and regards the rectangular region 4 as a touchpanel with force sensing function of a laptop computer to perform apseudo process. FIG. 1B illustrates a state in which a finger isattached and placed on a wide range on the panel.

FIG. 1C is a schematic diagram describing a second state (state withpush operation) of two states to be distinguished by the pushdetermination function of the touch sensor 1. A keyboard 41 and a touchpush button 42 are displayed as graphical user interfaces on the panel2. In such a case, although the graphical user interfaces are displayed,the user may use the interfaces as user interfaces with actualmechanical push switches, and the user may strongly press the indicator3 against the panel 2. The push determination function of the presentdisclosure determines that the state with a strong push on the graphicaluser interface is the second state with push operation and distinguishesthe second state from the first state.

FIG. 2 is an overall flowchart of a push determination method common tothe embodiments. The flow will be described, and state transition willbe described.

First, the initial state is set to a state SO that is a non-touch state.Dashed ellipses in FIG. 2 indicate states. In the state SO, touchdetection for detecting whether the indicator 3 is approaching isperformed (S100).

FIG. 3 is a flowchart of the touch detection at S100.

First, the level value C at each position of M×N cross points isacquired (S101). Whether a maximum value Cp of the M×N level values C issmaller than a predetermined detection threshold T is determined (S103).If the maximum value Cp is smaller than the detection threshold T(S103Y), data N indicating that there is no touch is internally output.If the maximum value Cp is equal to or greater than the detectionthreshold T (S103N), data Y indicating that there is a touch is output.

FIG. 4A depicts a state in which the indicator 3 weakly touches thepanel 2 (normal touch operation). FIG. 4B depicts an example of atwo-dimensional distribution of the level values C in the weak touchoperation state. Assuming that the value of the detection threshold T is10 in the operation flow of FIG. 3, the level values C greater than thedetection threshold T are detected at two intersection points in theexample of FIG. 4B, including an intersection point of the row electrodeY4 and the column electrode X6 and an intersection point of the rowelectrode Y4 and the column electrode X7. Therefore, the data Y isoutput. Note that in the following description, a large level valuecorresponds to a large amount of change in the capacitance due to theapproach of the indicator 3. The level value may be indicated by eithera plus sign or a minus sign, and in the description here, the levelvalue indicates a positive value when the indicator 3 approaches.

FIG. 2 will be further described. If a touch is not detected in thestate S0 (S100N), the state S0 is repeated. If a touch is detected inthe state S0 (S100Y), the state S0 shifts to a state S1 that is a singletap state.

The state S1 is a state in which a touch is already detected once and isa state for determining whether the touch is a single tap or a doubletap. Therefore, the touch detection is performed again (S100), and ifthere is no touch (S100N), the touch detection is further performed fora certain time (S110). If a touch is still not detected, a single tapevent Est is output as the event E. On the other hand, if a touch isdetected during the performance of the touch detection for a certaintime, the state S1 shifts to a state S2 that is a double tap state. Anoperation equivalent to the operation in the state S1 is performed inthe state S2, and a double tap event Edt is output.

In the state S1, if a touch is detected at S100 (S100Y), the state S1shifts to a state S3 that is a touch detection state. In the state S3,touch detection involving push determination is performed (S130).

FIG. 5 is a flowchart of the touch detection involving the pushdetermination according to the present embodiment.

First, the level value C at each position is acquired (S501).

Next, whether the maximum value Cp of the level values C is smaller thanthe detection threshold T (for example, value 10) is determined (S503).

On the other hand, if the maximum value Cp is smaller than the detectionthreshold T (case of S503Y), the data N indicating that there is notouch is internally output as an event, and the touch detection ends. Onthe other hand, if the maximum value Cp is equal to or greater than thedetection threshold T as a result of the determination at S503 (case ofS503N), the push determination described at S505 is performed.

At S505, a region R (tracking region R) as a target of the same trackingprocess as a tracking process of the position where the maximum value Cpis output is specified. The tracking process is, for example, a processof specifying whether there is the same one finger or there are twodifferent fingers in multi-touch detection using a plurality of fingers.For example, the level values at positions in eight directions around atarget position, such as the position where the maximum value Cp isoutput, are acquired. When the level values are greater than apredetermined value, the positions are handled as the same region as thetarget position, and the same level value is provided. In this way,individual tracking regions R are specified in the process.

Next, area data S of the tracking region R and sum total data Σ of thelevel values C at the positions included in the tracking region R areoutput S507.

The area data S is data corresponding to the size of the two-dimensionalarea of the tracking region R. For example, the area data S may be thenumber of intersection points. According to the example, the value ofthe area data S1 is 2 in the case of FIG. 4B. The area data S may bedata for deriving the area, such as a length and a width, instead of thedata indicating the area itself. For example, the area data S mayinclude a length SL or a width SW of the tracking region R. Since thetracking region R is 1 row ×2 columns in the example of FIG. 4B, a value“2” of the length SL may replace the area data S, and the value “2” maybe set as area data. The area data S may be data corresponding to one ofa long side of rectangle or a major axis of ellipse regarding thetracking region, a maximum distance from the center of gravity of theregion, and a maximum length between two positions in the region.

Next, the sum total dataΣ is data corresponding to a sum total value ofthe level values C at the positions included in the tracking region R.In the case of FIG. 4B, the value of the sum total dataΣ is 21. Notethat the value of the sum total data Σ may be a value obtained byapplying predetermined calculation or modification to the level values,instead of the sum of the level values C. The sum total dataΣ indicatesa volume V when the level value at each position on the two-dimensionalmap is regarded as the height, and in that respect, the sum total data Σcan also be referred to as volume data.

In the first embodiment, both of these two types of data are necessaryfor distinction between (a) outputting data corresponding to the pushoperation in the case of a strong push with a fingertip (second state,FIG. 1C, FIG. 6B described later) and (b) outputting data correspondingto the touch operation when there is equal to or greater than apredetermined amount of change in the capacitance in a wide range suchas when a finger is attached to the touchpad (first state, FIG. 1B, FIG.7B).

First, FIG. 6A is a cross-sectional view illustrating the state (a) ofthe case of a strong push with a fingertip (push operation) in thesecond state described in FIG. 1C. In the case of a strong push with afingertip as in FIG. 6A, the capacitance formed between the indicator 3and neighboring electrodes (row electrode Y4 and column electrode X6)leads to an increase in the values of the detected level values Ccompared to the state of FIG. 4A due to various factors, such as adecrease in a distance d caused by local deflection, an increase in thearea S functioning as an electrode due to deformation of the fingertip,and insertion of a finger with a high dielectric constant ε. FIG. 6Bdepicts an example of a two-dimensional distribution of the signal levelin the push operation. In the example of FIG. 6B, the value of the areadata S is 4 (value of length data SL is 2, value of width data SW is 2),and the value of the sum total dataΣ is 81. Each value is locally largerthan the value in the example of FIG. 4B.

FIG. 7A corresponds to the first state described in FIG. 1B and is across-sectional view illustrating the second state (b) generated whenthere is equal to or greater than a predetermined amount of change inthe capacitance in a wide range such as when a finger is attached to thetouchpad. FIG. 7B illustrates an example of a two-dimensional map of thelevel values C detected in the state. In the example of FIG. 7B, thearea data S with a value of 8 (value of length data SL is 4, and valueof width data SW is 2) is large, and the sum total dataΣ with a value of81 that is the sum total of the level values C is large.

The values of the sum total data Σ are the same in the examples of FIGS.6B and 7B. Therefore, if only the sum total data Σ is used to detect thepush operation, the state of FIG. 7A cannot be excluded, and there is aproblem that the state is falsely determined.

On the other hand, both of the sum total data Σ of the signal level andthe area data S are used in the disclosure according to the presentembodiment, and the area data S and the sum total data Σ are used toperform the push determination (S520) to thereby distinguish the twostates.

First, whether the value of the sum total data Σ of the level values Cof the region is greater than a predetermined value (volume value) TV isdetermined (S521). As a result of the determination at S521, if thevalue of the sum total data Σ is smaller than the value TV, it isdetermined that the normal touch operation is performed instead of thepush operation, and the touch event Etd is output as a value of theevent E.

On the other hand, if the value of the sum total data Σ is greater thanthe value TV as a result of the determination at S521, the value of thearea data S is further compared with a predetermined value (area value)TS (S522). As a result of the comparison at S522, if the value of thearea data S is smaller than the value TS (S522N), that is, if the levelvalues C are increasing only locally, it is estimated that the pushoperation is performed, and the push event Epd is output as a value ofthe event E.

On the other hand, if the value of the area data S is larger than thevalue TS as a result of the comparison at S521, it is determined thatthis is the case (b) in which there is equal to or greater than apredetermined amount of change in the capacitance in a wide range suchas when a finger is attached to the touchpad, and the normal touch eventEtd is output as the event Σ instead of the push event Epd.

In this way, according to the disclosure of the present embodiment, thepush operation is extracted based on the sum total data Σ of the signallevel, and whether the value of the sum total data is in a local rangeor a wide range is determined based on the area data S. This enables thedistinction according to the signal level value per unit area. As aresult, even for the same value of the sum total data Σ as in FIG. 6Band FIG. 7B, the push determination function can be realized, in whichthe data corresponding to the push operation is output when the changelevel of the capacitance is locally increased due to a strong push witha fingertip, and the operation is not mistaken for the push operationwhen the capacitance is changed in a wide range such as when a finger isattached to the touchpad.

Note that in the present embodiment, the push operation determination isnot limited to the determination directly using the sum total data Σ andthe area data S. For example, a power density derivation of acquiringthe level value per unit area based on the sum total data Σ and the areadata S may be included, and whether to output the event corresponding tothe touch operation or to output the event corresponding to the pushoperation may be determined based on the level value per unit area.

Second Embodiment

FIG. 8 is an operation flowchart of the touch detection with pushdetermination (S130) according to a second embodiment.

Acquiring an amount of time change dΣ of the sum total data Σ isincluded in the present embodiment. In the push operation determination,whether to output the touch event Etd corresponding to the touchoperation or to output the push event Epd corresponding to the pushoperation is determined based on the sum total data Σ, the area data S,and the amount of time change dΣ of the sum total data.

First, as in the first embodiment, the level value C at each position isacquired (S801), and the tracking region R as a target of the sametracking as tracking of the position where the maximum value Cp isoutput is specified (S803). Next, the sum total data Σ of the trackingregion R is acquired (S805).

Next, at S807, the amount of change dΣ between the sum total data Σ andsum total data Σlast of the last time is derived (S807).

During the push operation, the value of the amount of time change dΣaround the same tracking region R of the sum total data Σ tends to belarger than during the touch operation. According to the operation flowof the modification, the accuracy of distinction between the pushoperation and the touch operation can be increased. Therefore, theamount of time change dΣ is added as a criterion for determination.

First, whether the tracking region R is positioned near a trackingregion Rlast of the last time is determined (S809). If the trackingregion R is not positioned near the tracking region Rlast of the lasttime (S809N: far), the touch event Etd is output as the event E.

On the other hand, if the tracking region R is positioned near thetracking region Rlast of the last time (S809Y), whether the amount oftime change dΣ is greater or smaller than a predetermined value isdetermined. If the amount of time change dΣ is greater than thepredetermined value (Y in S811), data corresponding to the push eventEpd is output as the event E.

On the other hand, if the amount of time change dΣ is smaller than thepredetermined value (S811N), data corresponding to the touch event Etdis output as the event E. Lastly, the tracking region R and the sumtotal data Σ in the detection of this time are held as the trackingregion Rlast and the sum total data Σlast of the last time for the nextdetection (S813).

According to the disclosure of the present present embodiment, theposition of the tracking region R and the amount of time change Σ of thelevel value C of the sum total data Σ are used to determine whether theamount of time change dΣ at a predetermined position is increased. Thiscan improve the determination accuracy of the push determination fordetermining whether the push operation is performed or the touchoperation is performed.

Although the preferred embodiments of the present disclosure have beendescribed, the present disclosure is not limited to the embodiments inany sense, and it is obvious that the present disclosure can be carriedout in various modes without departing from the scope of the presentdisclosure.

For example, the disclosures of the embodiments may be combined. Thefirst embodiment may further include acquiring the amount of time changeof the sum total data, and in the push operation determination, whetherto output the event corresponding to the touch operation or to outputthe event corresponding to the push operation may be changed based onthe sum total data, the area data, and the amount of time change of thesum total data.

In the embodiments, the operation flows of FIGS. 5 and 8 may be dividedinto acts performed by the integrated circuit 10 and acts performed bythe host controller 20. For example, in the first embodiment, theintegrated circuit 10 may output the sum total data E and the area S tothe host controller 20, and the host controller 20 may perform the pushdetermination at S520 of FIG. 5 based on the data.

What is claimed is:
 1. A method performed by an integrated circuitconnected to a touch panel used with a display apparatus that displays agraphical user interface, the method comprising: acquiring level valuesindicating changes in capacitance at positions in a two-dimensionalregion of the touch panel; detecting a touch to the touch panel by anindicator based on a maximum value of the level values at the positionsin the two-dimensional region; specifying a tracking region of aposition where the maximum value is output; outputting area datacorresponding to a size of the tracking region and sum total datacorresponding to a sum total value of the level values at the positionsincluded in the tracking region; and in a case where the sum total dataindicates the sum total value is greater than a predetermined sum totalvalue, (a) determining an event corresponding to a push operation is tobe output when the area data indicates a second area value smaller thana first area value, or (b) determining an event corresponding to a touchoperation is to be output when the area data indicates the first areavalue.
 2. The method according to claim 1, wherein the area dataincludes length data of the tracking region, and the method furthercomprises: in a case where the sum total data indicates thepredetermined sum total value, (a) outputting the event corresponding tothe touch operation when the length data of the tracking regionindicates a first length value, and (b) outputting the eventcorresponding to the push operation when the length data of the trackingregion indicates a second length value shorter than the first lengthvalue.
 3. The method according to claim 2, wherein the length data ofthe tracking region corresponds to one of: a long side of rectangle or amajor axis of an ellipse regarding the tracking region, a maximumdistance from a center of gravity of the tracking region, or a maximumlength between two positions in the tracking region.
 4. The methodaccording to claim 1, further comprising: acquiring a level value perunit area based on the sum total data and the area data, wherein thedetermining the event corresponding to the touch operation is to beoutput or the determining the event corresponding to the push operationis to be output is based on the level value per unit area.
 5. The methodaccording to claim 1, further comprising: acquiring an amount of timechange of the sum total data; and changing a determination whether tooutput the event corresponding to the touch operation or to output theevent corresponding to the push operation based on the sum total data,the area data, and the amount of time change of the sum total data.
 6. Amethod performed by an integrated circuit connected to a touch panel,the method comprising: acquiring level values indicating changes incapacitance at positions in a two-dimensional region of the touch panel;detecting a touch to the touch panel by an indicator based on a maximumvalue of the level values at the positions; outputting sum total data ofthe level values of a tracking region that is positioned around aposition where the maximum value is output; acquiring an amount of timechange of the sum total data; and determining whether an eventcorresponding to a touch operation is to be output or an eventcorresponding to a push operation is to be output based on the amount oftime change of the sum total data.
 7. The method according to claim 6,wherein the determining whether the event corresponding to the touchoperation is to be output or the event corresponding to the pushoperation is to be output includes: determining the event correspondingto the touch operation is to be output when the amount of time change ofthe sum total data is smaller than a predetermined change value, anddetermining the event corresponding to the push operation is to beoutput when the amount of time change of the sum total data is greaterthan the predetermined change value.
 8. The method according to claim 7,wherein the determining whether the event corresponding to the touchoperation is to be output or the event corresponding to the pushoperation is to be output includes: when the sum total data indicates avalue greater than a predetermined sum total value, (a) determining theevent corresponding to the touch operation is to be output when an areaof the region indicates a first area value, and (b) determining theevent corresponding to the push operation is to be output when the areaof the region indicates a second area value smaller than the first areavalue.